HVAC-Talk site will be slow for the next few days. It's normal site/server maintenance. Thx -Dad

Welcome to HVAC-Talk.com, a non-DIY site and the ultimate Source for HVAC Information & Knowledge Sharing for the industry professional! Here you can join over 150,000 HVAC Professionals & enthusiasts from around the world discussing all things related to HVAC/R. You are currently viewing as a NON-REGISTERED guest which gives you limited access to view discussions

To gain full access to our forums you must register; for a free account. As a registered Guest you will be able to:

Participate in over 40 different forums and search/browse from nearly 3 million posts.

Is there any set standard for humidity reduction while running the AC?? Most of the posts I have seen related to humidity are when they system does not pull enough out. Can a system take too much humidity out?

Humidity in the range of 50% to 60% seems to be the accepted "standard" for residential air conditioning. I guess that range is a good compromise of comfort and cost. You don't want it much above 60% because then you might turn your house into a mold farm. You don't want it too low because it costs money to reduce it. If you have asthma or some other respiratory problems humidity in the range of 30% to 40% may be recommended.

Carpeting on concrete requires 50%RH in the air. Under the carpet, the temp is cooler,6-8 ^F. That makes the %RH 10-15% higher. 60%RH under the carpet is max. Also +60%RH grows dust mites. 50-55%RH ideal for summer. Winter should be low enough the avoid condensation on the inside of windows.

under normal conditions the answer to your question is no. A properly sized system works 70% on cooling the air and 30% removing the humidity. You would reach set temp before to much humidity was removed.

Decreasing the airflow over the evaporator coil will increase the moisture removal. That is, more of the total system capacity is devoted to removing grains of water vapor from the air. This is called the sensible heat factor.

A sensible heat factor of 1.0 means no moisture is being removed. All the capacity is used to remove sensible heat and lower the air temperature. A lower sensible heat factor such as .75 means that 75% of the system's total capacity is removing sensible heat and the other 25% is dehumidifying.

The sensible heat factor can be manipulated by changing the airflow or fan speed. Newer systems using ECM supply fan motors often have speed adjustments and/or humidity adjustment which vary the airflow to match the dehumidification needs of the home.

There is a need to limit how low the airflow is allowed to go so as to protect the compressor from liquid floodback.

Originally posted by teddy bear Carpeting on concrete requires 50%RH in the air. Under the carpet, the temp is cooler,6-8 ^F. That makes the %RH 10-15% higher. 60%RH under the carpet is max. Also +60%RH grows dust mites. 50-55%RH ideal for summer. Winter should be low enough the avoid condensation on the inside of windows.

Get real,hundreds of homes with carpeting ,vapor seal under the slab, in Florida with slabs and no problems,do you sell something???